2G2 THE VOYAGE OF H.M.S. CHALLENGER. 



2. Rhizocrimis rawsoni, Pourtal^s, 1874 (PI. IX. figs. 3-5; PI. X. figs. 3-20; 

 PI. LIII. figs. 7, 8 ; woodcut, fig. 19). 



1872. Rhizocrinus lofotensis, Wyv. Thorns, (pars), Proc. Eoy. Soc. Edin., vol. vii. p. 770; The Depths of 



the Sea, 1873, p. 450. 

 1874. Rhizocrimis Rawsonii, Pourtales, IIL Cat. Mus. Comp. Zool., vol. iv., No. 8, p. 27. 



1882. Rhizocrinus rawsoni, P. H. Carpenter, Bull. Mus. Comp. Zodl., vol. x.. No. 4, p. 173. 



1883. Democrimts Parfaiii, Perrier, Comptes rendus, t. xcvi., No. 7, p. 450. 



1883. Rhizocrimis rawsoni, P. H. Carpenter, Ann, and Mag. Nat. Hist., ser. 5, vol. xi. p. 335. 



1884. Rhizocrimis rawsoni, P. H. Carpenter, Proc. Roy. Soc. Edin., voL xii. p. 357. 



Dimensions: 



Greatest length of entire specimen (Captain Cole), 



190-0 mm. 



180-0 „ 



6-0 „ 



2-5 „ 



75-0 „ 



Greatest length of stem, sixty-eight joints ("Blake" specimen), 

 Greatest length of calyx (" Blake "), .... 

 Greatest diameter of same calyx, .... 

 Greatest length of arm, sixty double joints (Captain Colo), 



Stem robust, bearing few radicular cirri on its lower part, but ending below in a long 

 spreading root which attaches itself at intervals. The joints are from once and a half 

 to twice (rare) as long as broad, and tolerably cylindrical or barrel-shaped in outline. 

 The planes of the articular ridges at their ends cross one another, but the ends are not 

 much expanded, so that the dice-box shape is but little marked. The calyx is very 

 variable in form, sometimes long and slender, sometimes short and broad. The expansion 

 from below upwards is rarely quite uniform, and there is often a more or less defined 

 constriction about the level of the basiradial suture. The basals are separated by 

 distinct sutures, and are generally four or more times the height of the radials, which are 

 five in number, and more or less distinctly pentagonal. 



The arms may have one hundred and twenty joints united in paii's by syzygy. The 

 first brachials are flattened, quite free laterally, and wider than long. The second are 

 more nearly square, and the next four shorter but of about the same width, the last one 

 (or the epizygal of the third syzygial pair) often bearing the first pinnule. The following 

 hypozygal joints are obliquely oblong ; while the epizygals are more irregular in shape, 

 and sometimes almost triangular, so as to look like axillaries. The first pinnule is 

 generally on the sixth or eighth brachial, but sometimes not till the fourteenth. The 

 two lowest joints of the basal pinnules are broader than their successors, which are 

 elongated and of gradually diminishing width. 



The peristome is about at the level of the sixth brachial, and is protected by small 

 oral plates. 



Colour, in spirit, brownish-white or greyish-white. 



Localities.~RM.^. " Porcupine," 1869. Station 42. Ofi" Cape Clear, lat. 49° 12' N., 



' Some other measurements of particular details will be found on p. 265, where also reference is made to the 

 unusually elongated calyx of the individuals dredged by the " Travailleur." 



